It is known in the diesel engine art to provide a fuel injection system wherein an engine driven pump supplies fuel at a relatively low pressure to injectors or injection pumps, with an excess capacity of non-injected fuel being returned through a return line to the supply tank. It is usual also to provide means to control the amount of fuel injected by the fuel injectors or pumps. Such means may include an engine mounted governor or other control device having a run-stop control lever or other mechanism movable to run and stop positions to respectively permit or prevent the injection of fuel and consequently allow or stop operation of the engine.
Under some circumstances, it has been found that some engines of the type described may be inadvertently caused to operate in a reverse direction of rotation or started by bumping of a vehicle in which such an engine is installed which has been parked in gear. It is desired to provide a unified system, controllable by an operator, to stop operation of the engine when desired and also to provide protection against unintentional bump starting and inadvertent operation of the engine in a reverse direction of rotation.